Optimization of Drought Limited Water Level and Operation Benefit Analysis of Large Reservoir

Abstract As an important water conservancy engineering project, reservoir regulation plays a crucial role in the insurance of water resources supply and demand balance and sustainable development and utilization, especially during drought seasons. The drought limited water level (DLWL) is the characteristic controlling water level of reservoir regulation operation during dry seasons, and the construction of reliable controlling schemes of DLWL is of great significance for the improvement of regional water resources utilization efficiency. Therefore, basing on the variation analysis of water inflowing series and water resources utilization characteristics among different sectors of Meishan Reservoir in Shihe Irrigation Area of China, firstly, the Hausdorff Dimensional Fractal (HDF) method was applied to divide drought early-warning periods of Meishan reservoir. Then, the initial scheme of DLWL of reservoir was determined through reservoir water inflow and water supply processes analysis during each drought warning periods of different typical hydrological years. And finally, the optimal dynamic controlling scheme of DLWL, described by drought warning water level (DWWL) and drought depleted water level (DDWL) respectively, was eventually proposed in this study based on the establishment of simulation and regulation model of reservoir and irrigation areas system. Moreover, the reliability and effectiveness of the proposed optimal controlling scheme of DLWL was further testified in terms of drought risk analysis of reservoir and irrigation area system under typical consecutive and annual drought scenarios, and meanwhile, the agricultural crop yield loss risk due to drought events corresponding to different controlling schemes of DLWL was also determined. The related research findings of this study could be favorable and beneficial for guiding drought-resistance regulation of reservoir and irrigation area system during drought seasons and providing reasonable decision-making basis of water resources utilization schemes as well.